Vania



F. CONRAD.

RADIOIELEGRAPHY SYSTEM.

APPLICAHON FILED JUIIE 5. I986.

Patented Sept. 2, 1919.

3 SHEETS-SHEET I.

WITNESSES INVENTOR F. CONRAD.

RADIUTELEGRAPHY SYSTEM.

APPLICATION man mu: 5. 1916.

1,3 14,789. v Patented Sept. 2, 1919. r

WITNESSES INVENTOR F. CONRAD.

amlomeemnv system.

APPLICATION FILED IN! 5- IQIG.

Patented Sept. 2, 1919.

3 SHEETS-SHEET 3.

INVENTOR Frank [unmd 7 A'ILI'ORNEY UNITED STATES PATENT OFFICE.

FRANK CONRAD, 0F SWISSVALE, PENNSYLVANIA. ASSIGNOR TO WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA.

RADIOTELEGRAPHY SYSTEM.

Specification of Letters Patent.

Patented Sept. 2, 1919.

To all whom it may concern:

Be it known that I, FRANK CoNnAp, a minzcn of the United States, and a resldent of Swissvale, in the count of Allegheny and. State of Pennsylvania, ave invented a new and useful Improvement in Radiotelegraphy Systems, of which the following is a specification.

My invention relates to systems employed for signaling by means of electric waves that are projected through space without the use of conducting wires.

More particularly, my invention relates to improvements in space-signaling or radiotelegraph systems that embody means for controlling the high-frequency oscillating circuits of such systems without employing interrupters, as keys or key-relays in the main .circuits which carry heavy currents and have high self-induction. Such a system has been proposed for use with alternating current generators and ordinary induction coils, the former supplying energy to the high-frequency oscillation circuit, and the latter being utilized for initially ionizing the oscillation producer included in the highfrequency circuit. Since the induction coil cannot be synchronized with the alternating current generator, there is no assurance that the ionization of the spark gap of the oscillation producer will occur at the proper time or the proper point in the alternatmg current wave of the supply generator to cause the most satisfactory operation of this system.

It is recognized that to render the receiving apparatus of a radio system most effective, the impulses impressed upon the receiving circuit should occur at the rate of about 1,000 impulses per second, which corresponds to the frequency or pitch of a tone of good audibility. To insure uniformity in the production of the tone in the receiving circuit and also the production of a note having a constant pitch, these impulses should be produced at regular as well as frequent intervals. It is apparent, therefore, that the ionization of the spark gap in the high-frequency oscillating circuit should be produced at regular intervals and with a suitable frequency in order to generatev and radiate from the antenna a series of wave trains having substantially the same initial amplitudes t. at will be instrumental in pro ducing in the receiving apparatus an audible note of constant pitch or uniform tone.

An object of my present invention, therefore, is to provide means for accomplishing the aforementioned results whereby the radiations emanating from the antenna may be produced at a high rate and at a uniform frequency in order to insure the production of a uniformly-pitched and audible note in the receiving apparatus. I accomplish these results without using a high-frequency alternator, but by employing the usual Hertzian oscillation circuit.

For a better understanding of the nature and scope of my invention, reference may be had to the following description and the accompanying drawings in which Figure 1 indicates diagrammatically an arrangement of apparatus employed in connection with a radio-telegraph system that embodies a form of my invention; Fig. 2 is a diagrammatic view showing a modified form of the system shown in Fig. 1; Figs. 3 and 4 are diagrammatic views showing my invention applied to radio-telegraph systems that are furnished with energy from two-phase and three-phase power supply circuits, respectively; Fig. 5 is a diagrammatic view showing my invention applied to a radio-telegraph system that embodies means for uniformly producing wave trains of such a frequency as will produce a properly pitched audible note in the associated receiving apparatus; and Figs. 6 and 7 are diagrams to llustrate the operation of the high-frequency ionizing circuits of Fig. 5.

In Fig. 1, a direct-current source of power supply 1 is connected by means of conductors 2 and 3 to a condenser 4 which may be of any of the usual types employed in connection with radiotelcgraph systems or circuits adapted toproduco Hertzian oscillations or electric waves. The condenser 4 by thus being supplied with direct current from a source of adequate power supply is maintained charged to substantially its full capacity at all times excepting at the instants of discharge. as will be hereinafter explained. A suitable inductance device 5 may be placed in circuit with the condenser 4 which will assist in maintaining the regularity of the sparks produced by a sparkproducer or electric-wave or oscillation roducer 6 associated with the condenser. he

oscillation producer 6, in this instance, is shown as comprisin two pairs of spaced electrodes 7 and 7 firmed of suitable metals or other material, and auxiliary ionizing electrodes 8 and 8 the function of which will be hereinafter ind icatcd. The high frequency circuit in which the electrical waves or oscillations tl'iat are to be projected into space by the radio-system are developed comprises the COI'KlOll-SBI 4, the oscillation producer 6 and the primary winding 9 of an oscillation transformer 10 which may be of any usual form commonly employed in connection with radio-systems. The second ary winding 11 of the oscillation transformer 10 has one of its terminals grounded at 12 and the other connected to an adjustable inductance device 13 which, in turn, is electrically connected to an antenna or electric-wave radiator 14. The windings 9 and 11 may be loosely or closely coupled. It is usually preferable. however, to closely con ph these two windings of the oscillation transformer in order to insure that a substantial amount of the energy flowing in the pri n'iary circuit will be transferred to the secondary circuit comprising the electric-Wave radiator 14. Moreover, the coupling action may be improved if the primary and secondary circuits of the oscillation transformer are in resonance. Again, if proper quenching of the sparks generated by the oscillation producer 6 is effected, the high-frequency oscillations in the primary circuit will discontinue after a very short time interval and the secondary circuit will continue to oscillate at its natural frequency and with its natural damping just as if the primary circuit did not exist. The effectiveness of the radiations emanating from the antenna 14 is, therefore, dependent upon the oscillation decrement of the secondary circuit, the amplitudeof the initial vibrations, the rapidity and regularity of the wave trains produced, and the quenching action obtaining in the primary circuit.

To produce high-frequency oscillations in the primary circuit of the oscillation transformer 10, it is necessary to effect discharges at proper times between the electrodes 7 and 7". The initial discharges being effected, a veryhigh-frequency oscillating current flows for an instant in the primary circuit by reason of the repeated charging and discharging of the condenser 4. The amplitudes of the high-frequency currents thus generated are constantly decreasing in value because of the damping action of the resistance of the primary and secondary circuits. This is a usual way 'of generating electromagnetic oscillations that are to be'radiated from the antenna of a radio-system. It will be noted that each time one or the other of the spark gaps of the oscillation producer 6 is ionized, a wave train is propagated into sending circuits of the figure.

space from the antenna 14. Moreover, each one of the wave trains thus emanated produces a single impulse in the receiving apparatus of the associated receiving circuit.

To produce in the receiving appuralus an audible note of proper and uniform pitch, it is desirable to generate in the transmitting circuit, wave trains in the order of 1000 per second which are generated with uniform regularity or frequency in the highl reqnency oscillation circuit. To accomplish this. the ionizing electrodes 8 and 8 are successively energized by means of a control circuit 15 which comprises secondary windings 16 and 16 of spark coils 17 and 17*, the corresponding terminals of these windings being connected to the ionizing electrodes 8 and 8, lcspectively, and the other terminals of the e coils being connected to corresponding electrodes of the spark gap members of the oscillation pl'fldllk'fil' (i, in this instance the electrodes 7. Primary u'indingv 1H and 1%" of the spark coils 1'! and 17 are connected through interrupters 19 and 19 and an ordinary telegraph key 20 to a source of power shown as a battery 21. The source of power 21. may be of relatively small capacity and entirely independent of the ener y flowing in the main circuits of the rad1o-system. Each of. the interrupters 19 or 19 comprises two cooperating contact members 22, the upper one being supported on a spring-actuated member 23, and a rotating cam member 24 which is connected by means of a shaft 25 to any high variable speed propeller, such as a motor (not shown.) The can] members 221 are provided with a series of spaced toothed portions 26 and 26 which periodically intcrrupt the re pective circuits of the prithe primary windings of the spark coils The toothed portions 26 and 26" are so related with one another by reason of the relative displacement of the cam members 24 and 24 that they alternately actuate with regular uniforn'iity the spring members 23 and 23 of the interrupters, thereby alter-- nately exciting with uniform regularity the primary windings of the spark coils 17 and 17' when the pressed. If the cam members 24 and 2-1 are rotated at a proper speed to energize each spark coil at the rate of 500 times or thereabout per second, the energization of the coils being effected alternately, 1,000 wave trains per second will emanate from the antenna 14 which insure the production of a uniformly toned and audible note in the receiving apparatus associated with the Of course, the spark coils 1.7 and 17 will be energized during the time only that the key 20 is depressed. Condensers 25" are connected across the contact members 22 of the interraptors in order to eliminate the sparking key 20 is dethat tends to destroy the active surfaces of the contact members.

To explain the operation of my system more particularly, assume that the condenser 4 has a large electrostatic capacity and that the source of direct current supply 1 is of adequate capacity to substantially instantaneously charge the condenser 4 each time that it discharges by reason of the energization of the spark gaps of the oscillation producer 6. The electrodes 7 and 7 are spaced a sufiicient distance from each other to preclude the occurrence of any discharges between them when subjected to any voltage that may be intentionally impressed on the condenser 4, and while the oscillation producer 6 is uninfluenccd by the auxiliary control circuit 15. To generate high-frequency oscillations in the primary circuit of the oscillation transformer 10, it is necessary to effect initial discharges between the electrodes 7 and 7 in order that the energy stored in the condenser 4 may be transferred in the form of electromagnetic wave trains to the antenna 14 from which they are propagated into space. When the shaft 25 is rotated at the proper speed to insure 500 interruptions or thereabout per second in each of the rimary circuits of the spark coils 17 and 1 1000 initial discharges per second are established between the ionizing electrodes 8 and 8 and the associated electrodes 7 of the oscillation producer 6, when the key 20 is depressed. The space between each pair of electrodes '7 and 7*.is, consequently, ionized at the rate of 500 times per second which render it conducting to the electric charge contained in the condenser 4. 'Since the spark gaps are alternately energized, the condenser 4 will, therefore, discharge 1000 times per second, thereby establishing 1000 wave trains which are radiated from the antenna 14. The condenser 4 is recharged to substantially its full capacity during the time intervals existing between the alternate excitation of the ionizing electrodes 8 and 8. 1

It will be noted hat the making and breaking of the primary circuits of the spark coils is under complete control by reason of the interrupters 19 and the/speed control of the shaft 25. In this'm-anner, a uniformly toned note of audible frequency is produced in the receiving circuit by reason of the uniform and regular production of the wave trains in the main circuit of the transmitting apparatus. Since the condenser 4 is maintained chargedor rather instantaneously recharged after each discharge, it is unnecessary to time the energization of the ionizing electrodeSjS and 8, such as would be necessary if the condenser 4 were energized from an alternating current source of power su ply.

gvhile I have'sho-wn the oscillation producer 6 as comprising two spark gaps severally associated with spark coils 17 and 17", as many spark gaps may be employed as circumstances require. By increasing the number of spark gaps, the rate of making and breaking the primary circuit of each of the spark coils may be decreased in order that the condenser 4 may discharge at the same rate as above indicated. Again, while I have shown the oscillation producer 6 as bein composed of stationary spark gap mem ers of the ordinary type, it will be appreciated that any of the well known quenched spark-gap devices may be employed without, in any way, afl'ecting the operation of my system. Similarly, the high-frequency transformer 10 may be dispensed with, the primary circuit being coupled directly with the antenna 14, such as is well known in the art.

In Fig. 2, three mercury rectifiers or other asymmetric conductors, 27, 27 and 27, are inserted between a three-phase supply cir cuit 28 and the condenser 4 in order to furnish it with high-potential rectified currents. The rectifiers 27, 27 and 27 are severally associated with the three phases of the supply system 28 and are connected in series with one another in a well known manner.

The high-frequency oscillating circuit com-' rises the condenser 4, a plurality of oscilation producers 6, 6" and 6 which are connected in parallel, as shown, and an induetive winding 29 by means of which the circuit comprising the condenser 4 and the circuit comprising the antenna 14 are directly coupled. Corresponding electrodes 7 7 and 7 of the oscillation producers 6 6 and 6, respectively, are severally associated with ionizing electrodes 8*, 8 and 8, each of the said ionizing electrodes being respectively connected to secondary windings 16 16 and 10 of spark coils 17 17 and 17. 'The primary windings 18", 18 and 18 are each respectively connected through interrupters 19 19 and 19 to the battery 21 and the control key 20. The interrupters 19", 19 and 19" are each associated with rotatable cams 24", 24 and 24 that are mounted upon the common shaft 25, the shaft, in turn, being rotated by means of a high variable speed motor 25". Projections 26", 26 and 26 severally associated with the separate cam members 24", 24" and 24 are So disposed and spaced with respect to one another that, on depressing the key 20, the oscillation producers 6", 6 and 6 are successively ionized at a very high rate. The rate of discharging the condenser 4 is, therefore, dependent upon the rapidity of ionizing the gaps extending between the three oscillation producers 6, 6 and 0.

As mentioned above, the source of owersupply for the condenser 4 is of a equate capacity to substantially instantaneously recharge the condenser during the time interval existing between successive energizations of the Spark gaps in the oscillation producer. The rectified wave impressed upon the condenser 4 by the cnergizln circuit is of adequate uniformity and renders it unnecessary to time the energization of the 0scillation producer so as to have the condenser 4 discharge only at the crests of the waves in the rectified circuit.

The system shown in Fig. 3 conten'iplates the use of a two-phase energizing circuit and two high-frequency oscillating circuits which are so connected that the oscillations alternately produced in them are impressed upon the circuit comprisi the antenna 14. A two-phase alternator 3 supplies power to a transformer 31 and a transformer 32 each of which is shown as being severally connected to one of the phases of the alternator 30. A secondary winding 31' of the transformer 31 is connected directly across a condenser 33 and a secondary winding 32 of the transformer 32 is connected directly across a condenser 33. The inductive winding 29 is connected by conductors 34 and 35 to the two high-frequency circuits associated with the secondary windings 31" and 32". One of the terminals of the secondary winding 31 is connected to the'conduc- 1301' 35 through a pair of oscillation producers 36 and 36*, and the corresponding terminal of the secondar winding 32 is likewise connected to te conductor 35 through another pair of oscillation producers 37 and 37. In this manner, two

high-frequency oscillating circuits are connected across the inductive winding 29, one of said high-frequency oscillating circuits comprising the condenser 33 and the oscillation producers 36 and 36", and the other high freq-uency oscillating circuit comprising the condenser 33 and the oscillation producers 37 and 37". Corresponding electrodes of the oscillation .producers 36 and 36', 37 and 37 are associated with ionizing electrodes 38 and 38", and 39 and 39*, respectively. Each of the said ionizing electrodes is connected to the secondary or hightension coil of a spark coil, in such manner as explained in connection with Fig. 1. For example, the ionizin electrode 38 is connected through a. con uctor 40 to one terminal of the high-tension windi 41 of a spark coil 42, the other termina of which is connected'through a conductor 43cc an associated electrode 36 of the oscillation producer 36. The primary winding 44 of the spar-k coil 42 is connected through conductors 45 and 4.6 *to one terminal of ithe-battery 21. The iother terminal is connected through a conductor 47, an interrupter 48, a conductor 49 and the sending :key 20 110 the other terminal of the battery 21. he. intenmpter 48 is operated hummus c a member 50 in the manner heretofore explained in connection with the other systems illustrated. The cam members associated with the several spark coils are displaced with respect to one another so that the spark gaps of the oscillation producers associated with the condensers 33 and 33" are ionized at proper times to effect alternate discharge of the condensers 33' and 33.

Since the condensers 33 and 33" are energized from the two phases of the two-phase supply circuit, it is necessary to time or rather synchronize the excitation of the oscillation producers so that the condensers .33 and 33 will discharge at the proper points in the alternating current waves of the supply circuit, as will be hereinafter explained in detail.

In Fig. 4, I have shown a radio-system supplied with energy from a three-phase power supply circuit 51. A Y-connected primary winding 52 of a three-phase transformer 53 is energized by currents delivered from the circuit 51. Across the phases of a Y-connected high tension secondary winding 54 are connected condensers 55 that are severally associated with circuits in which high frequenc oscillations are successively produced. he condensers 55 are connected in Y -formation to a neutral point 5.5 which, in turn, is connected to the neutral point of the secondary winding 54 of the transtormer 53 by a conductor 55. The condensers 55 are severally associated with oscillation producers-56, corresponding electrodes of which are connected to a common conductor 56 which, in turn, connects them to the oscillating circuit comprising the antenna 14 and the inductive winding 29. This oscillating circuit is also connected by means of a con ductor 56 to the neutral point 55 of the condensers. Again,eaoh high frequency oscillator 56 is associated withuan ionizing electrode 57, which, in turn, is connected in circuit with its separate spark coil 58. Primary windings 58 of the spark coils 58 are interrupted in succession and after proper time-interyals by means of rotating cam members-59 associated with interrupters '60.

In this manner, the high-potential ionizing currents are generated to initially establish dischar es in the oscillation producers 56. It will e noted, therefore, that energy from the three phases of the transformer 53 will be successively impressed upon the an-- tenna circuit 14 which may propagate into space in rapid succession a large number of wave trains for signaling purposes.

in this system, it will be noted by referring to -the=drawingthat each condenser 55 is successively connected -in closed circuit with the inductive windin 29 as the correspond" oscillation pro more are energized. %he condensers 55 are successively energized, by the three phases of tlie-siiipplyv circuit 51 and, therefore, it is advisable to time the ionization of the oscillation producers in such a manner that the condensers will discharge when the several alternating current potential waves reach their maximum value. For instance, the ionizing electrodes 57 should preferably be excited twice.

per cycle of each of the clcctromotive-force waves of the three-phase supply. This permits of generating of six wave trains during the time of each cycle of each electrometive force wave of the supply circuit. To establish a suliicient number of impulses to generate an audible note in the receiving circuit, the frequency of the alternating current supply should be substantially 166 cycles per second which will generate about 1000 wave trains per second in the highfrequency oscillating circuit.

In Fig. 5, I have shown a system whereby 1080 similar wave trains per second may be radiated into space from the antenna of the wireless sending system, while the excitation of the high-frequency circuits is furnished from an ordinary 60-cyele alternating current supply circuit. A transformer 60 has its primary Winding 61 connected to supply main 62 which are connected to a source of three-phase currents (not shown). A Y- connected secondary winding 63 of the transformer 60 energizes a plurality of condensers 64 that are connected in Y-formation to a neutral point 65 which, in turn, is connected by means of a conductor 66 to the neutral point of the secondary winding 63. Each of the condensers 64 is associated with a high-frequency oscillation producer 67, the several high-frequency oscillation producers being connected to a. neutral point 68 that, in turn, is connected to a terminal 69 of the inductive winding 29 which terminates in the antenna 14. The neutral point 65 of the condensers and the energizing winding 63 is connected by means of a conductor 70 to the other terminal of the inductive Winding 29 Which, in turn, is connected to ground at 71. Each oscillation producer 67 is associated with an ionizing electrode 72. As mentioned above, each ionizing electrode 72 is connected to a terminal of a high-tension winding 7 3 of a spark coil 74, the several secondary windings 7 3 being connected to a. common conductor 75 that, in turn, is connected to the common point 68 of corresponding electrodes of the high-frequency oscillation producers 67. Primary windings 76 of the spark coils 74 have corresponding terminals connected to a common conductor 77 that, in turn, is connected to one side of the battery 21 which, as mentioned above, is utilized to intermittently energize the spark coils 74 when the key 20 in the control circuit 15 is depressed.

A contact-making device 78 comprising a commutating cylinder 79, a rotatable conducting arm 80 and a synchronous motor 81 for propelling said arm is employed to properly time the energization of the ionizing electrodes 72 in order to produce a series of similar wave trains, or wave trains having substantially the same initial amplitudes, in regular succession so that an audible uniformly-toned note may obtain in the receiving circuit associated with this sending sys term. The eommutating cylinder 79 comprises a plurality of uniformly spaced conducting segmcnts 82 that are arranged in six groups, each group consisting of three adjacent segments and oppositely-(iisposed groups of segments being interconnected with each other, as will be hereinafter explained. The conducting arm 80 is connected to one side of the battery 21 through a slip ring 83 which engages a brush 84. The arm 80 is connected to a shaft 85 of the synchronous motor 81 that, in turn, is con nected through leads 86 to the three-phase supply mains 62. In this instance, the motor is so designed as to rotate the conducting arm 80 at the rate of 60 revolutions per second.

The primary windings 76 of the spark coils 74-. are severally connected to the proper pairs of segment groups on the commutating cylinder 79; for instance, the primary winding 76 of the spark coil 74 is connected to the pair comprising groups 86 and 86 of the conducting segments 82. The group 86 comprises three adjacent conducting segments which are connected to one another by a conductor 87 and, similarly, the conducting segments of the group 86* are connected to one another by a conductor 87. The oppositely-disposed groups 86 and 86 are then connected to each other by means of a common conductor 88. In a similar manner, the primary windings of the other spark coils are connected to the other two pairs of groups of conducting segments, as will be observed by referring to the drawing. Since one terminal of the battery 21 is connected to the conducting arm 80 and the other terminal is connected to terminals of the rimary windings 76 of the spark coils 74 w ich, as mentioned above, are connected to the conducting segment 82, it will beapparent that each time the conducting arm 80 engages one of the conducting segments 82, the primary winding of the spark coil associated therewith will be energized and, consequently, as the conducting arm disengages said conducting segment, an eleetromotive force is induced in the corresponding secondary winding of the spark coil thereby energizing the proper ionizing electrodes 72. In this manner, the ionizing electrodes 72 are energized to intially establish ionizing arcs in the oscillation producers 67 that permit the condensers 64 to discharge through the high frequency oscillating circuits.

Again, by referrin to the drawing, it will be observed that one primary windin 7 6 of the three spark coils 74 is energize three timesin succession which energizations are so timed as to occur when the corresponding electromotive force wave of the sup ly source is near or at its maximum value. y timing the energizations of the primary windings of the three spark coils with regnlarity, 1080 wave trains per second are emanated from the antenna 14 b reason. of the 18 makes-and-breaks beinge ected in the primary windings of the spark coils during each revolution of the conducting arm 80 which, as mentioned above, rotates at the rate of 60 revolutions per second.

By referring to Fig. 6, I have shown a graphical representation of the three-phase electromotive force waves of the GO-cycle supply circuit. I have also represented time intervals that correspond to twenty electri' cal degrees by means of equally-spaced perpendicular lines 87. It is my intention to energize the several ionizing electrodes 72 at points in the waves indicated at 90. Both positive and negative halves of the electromotive force waves are utilized since the sign of the discharges is unimportant. Consider the electromotive force wave 88, that is represented by a rotatable vector 88" of Fig. 7, the positive direction being indicated by the arrow-head. The circuit upon which the electromotive force wave 88 is impressed is ionized by means of the device 79 three successive times as indicated by the lines 91, 91 and 91 which are spaced from one another by time intervals corresponding to 20 electrical degrees. After a time interval of 20 electrical degrees, the circuit u on which the electro-motive force wave 2 is impressed is ionized at three successive time intervals represented by the lines 93, 93 and 93". After another time interval of 20 electrical degrees, the circuit upon which the electromotive force wave 93 1s impressed is ionized three successive times as represented by the lines 94, 94 and 94". It will be noted from the foregoipig description that during each cycle of eac electromotive force wave each circuit is interrupted six times and, therefore, from a GUI-cycle three-phase circuit 1080 interruptions per second mag be effected b meansof the device 78 whic re sults in the propagation into space of 1080 wave-trains per second from the antenna 14, Since the initial amplitudes of the hi h frequency oscillations should correspon to the points 90 in the three electromotive force waves 88, 9,2 and 96, it may be necessary to impart a phase advancement, or, in other words, to advance the revolving arm 80 slightly in advance f sy hronous position in order to, ionize the auxiliary electrodes 7 2 an instantfprior to the electromotive force waves reaching their proper values.

Since the electromotive force waves 88, 92 and 96 have substantially the same values at the points indicated by the lines 91, 91, and 91", 93, 93 and 93 and 94, 94" and 94- respectively, and corresponding points, the initial amplitudes of the wave trains generatcd in the several high-frequency circuits will be substantially e ual in value. Therefore, it is apparent t at a properly-toned note of uniform and constant pitch will be obtained in the receiving circuit associated with the transmittin circuit of the figure. In this manner, and] le notes are received from circuits energized from an ordinary (ill-cycle, three-phase supply circuit. It is necessary, however, that the capacity of the power supply circuit be adequate to substantially instantaneously charge the condensers 64, since they are charged and rechar ed in very short time intervals.

W die I have shown and described several embodiments of my invention, it will be understood that many modifications may he made therein without departin from the spirit and scope of the appende claims.

I claim as my invention:

1. In a system of radio-signalin the combination with a polyphase suppg circuit and highfrequency oscillating circuits severally associated with the phases thereof, of an auxiliary circuit for controlling, in regular and uniform succession, the formation of high-frequenc Wave trains of oscillations in said high requency circuits.

.2. In a radiosignaling system, the combination with an electrostatic capacity element, a plurality of high-frequency oscillation producers associated therewith, and an antenna for space-radiating the resultant high-frequency oscillations, of an auxiliary circuit comprising a plurality of ionizing electrodes, spark coils connected thereto, interrupters severally associated with said spark coils, a source of electrical energy, and means for energizing said spark coils in rapid succession and at will, whereby said ionizing electrodes successively influence said hi h-frequency oscillation producers to estab ish trains of high-frequency oscillations in rapid succession.

8. In a radio-signaling system, the combination with a polyphase supply circuit, condensers severally associated therewith, a high-frequency oscillation producer associated with each condenser, and an antenna for space-radiating the resultin high-f requency oscillations, of an auxiliary circuit comprising ionizing electrodes severally associated with the oscillation producers of the separate phases of the supply circuit, andmeans for exciting said ionizing electrodes in succession in the several hases.

4. The combination with a polyp ase supply circuit, of high-frequency electricaloscillation-producing circuits severally associated with the phases ofisaid polyphase circuit, of an auxlliary circuit controlling the initial production of oscillations in said high-frequency circuits in succession, when properly excited, and means for exciting the auxiliary circuit at will.

5. The combination with a polyphase supply circuit, and a condenser circuit dis charging through a high-frequency oscilla- 10 tion producer associated with each phase of the polyphase circuit of an auxiliary circuit for initially ionizing said high-frequency oscillation producers in succession, when properly exclted, and means for exciting said auxiliary circuit at will.

In testimony whereof, I have hereunto subscribed my name this 31st day of May 1916.

FRANK CONRAD.

copies of this patent may be obtained for five cents each, by addressing the "commissioner 0! Patents, Washington, D. 0. 

